Transport properties of 2D-electron gas in a n-InGaAs/GaAs DQW in a vicinity of low magnetic-field-induced Hall insulator--quantum Hall liquid transition

TL;DR

This study investigates the transport properties of a low-mobility 2D electron gas in a double quantum well near the magnetic-field-induced transition between Hall insulator and quantum Hall liquid phases, revealing localization effects and Landau quantization.

Contribution

It provides new insights into the temperature-dependent localization and Landau quantization in low-mobility 2D electron gases near the Hall insulator-quantum Hall transition.

Findings

Resistivity shows insulating-like temperature dependence at low magnetic fields.

Localization and Landau quantization are linked to anomalous temperature dependence of sigma_xy.

The observed phenomena occur in the ballistic regime near the 2D metal-insulator transition.

Abstract

The resistivity (R) of low mobility dilute 2D-electron gas in a n-InGaAs/GaAs double quantum well (DQW) exhibits the monotonic 'insulating-like' temperature dependence (dR/dT < 0) at T = 1.8 -- 70K in zero magnetic field. This temperature interval corresponds to a ballistic regime (kTtau/hbar > 0.1 -- 3.5) for our samples, and the electron density is on a 'insulating' side of the so-called B = 0 2D metal--insulator transition. We show that the observed localization and Landau quantization is due to the Sigma_xy(T)anomalous T-dependence.